Organic light emitting display device and method of manufacturing the same

ABSTRACT

Disclosed is an organic light emitting display (OLED) device that may include first and second pixels on a substrate, each including a TFT region and a display region, the display region of each of the first and second pixels including a first electrode, an emission layer and a second electrode; a color filter layer in the display region of the second pixel; and a reflection preventing layer in the first and second pixels, substantially excluding the display region of the second pixel.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the Korean Patent Application No.10-2013-0136465 filed on Nov. 11, 2013, which is hereby incorporated byreference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relate to an organic light emitting display (OLED)device and method of manufacturing the same, and more particularly, toan OLED device provided with a reflection preventing layer and method ofmanufacturing the same.

2. Discussion of the Related Art

An organic light emitting display (OLED) device includes a lightemitting layer provided between a cathode for injecting electrons and ananode for injecting holes. When the electrons generated in the cathodeand the holes generated in the anode are injected into the inside of thelight emitting layer, excitons are produced by the recombination of theelectrons and the holes. Then, when the excitons fall to a lower energystate from an excited state, the OLED device emits light.

Hereinafter, an OLED device according to the related art will bedescribed with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view illustrating the OLED device accordingto the related art.

As shown in FIG. 1, the OLED device according to the related art mayinclude a substrate 10, a thin film transistor 20, a passivation film30, a color filter layer 40, a planarization layer 50, a first electrode60, a bank layer 65, a light emitting layer 70, a second electrode 80,and a reflection preventing layer 90.

The thin film transistor 20 is provided on an upper surface of thesubstrate 10. The thin film transistor 20 may include a gate electrode21 patterned on the substrate 10, a semiconductor layer 22 insulatedfrom the gate electrode 21 by a gate insulating film 15 interposedtherebetween, and source and drain electrodes 23 and 24 provided at afixed interval from each other and provided on the semiconductor layer22.

The passivation film 30 is provided on the thin film transistor 20.

The color filter layer 40 is patterned on the passivation film 30.

The planarization layer 50 is provided on the color filter layer 40. Acontact hole is formed in a predetermined region of the passivation film30 and the planarization layer 50, whereby a drain electrode 24 of thethin film transistor 20 is exposed via the contact hole.

The first electrode 60 is patterned on the planarization layer 50. Thefirst electrode 60 is connected with the drain electrode 24 via thecontact hole.

The bank layer 65 is provided on the planarization layer 50. The banklayer 65 is provided on a thin film transistor (TFT) region, to therebydefine a display region.

The light emitting layer 70 is provided on the first electrode 60, andis patterned on the display region defined by the bank layer 65. Thelight emitted from the light emitting layer 70 passes through the colorfilter layer 40 and then the substrate 10, to thereby display an image.

The second electrode 80 is provided on the light emitting layer 70.

The reflection preventing layer 90 is provided on a lower surface of thesubstrate 10, to thereby prevent external light from being reflected onthe lower surface of the substrate 10. As described above, the thin filmtransistor 20 is formed in the TFT region. Thus, the external light isreflected due to a plurality of signal lines for forming the thin filmtransistor 20. In this respect, the reflection preventing layer 90 isprovided on the lower surface of the substrate 10 so as to reduce orprevent the reflection of the external light.

However, in the OLED device according the related art, the reflectionpreventing layer 90, which is typically provided in a film type, isformed in both the TFT region and the display region, which lowers thelight transmittance of the display region and the luminance of the OLEDdevice. That is, when the light emitted from the light emitting layer 70of the display region passes through the substrate 10 and then thereflection preventing layer 90, a considerable amount of light isabsorbed in the reflection preventing layer 90, thereby causing a lightloss.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to an organic lightemitting display (OLED) device and method of manufacturing the same thatsubstantially obviates one or more problems due to limitations anddisadvantages of the related art.

An advantage of the present invention is to provide an OLED device thatis adapted to improve luminance by reducing or preventing a reflectionof an external light.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. These andother advantages of the invention will be realized and attained by thestructure particularly pointed out in the written description and claimshereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof embodiments of the invention, as embodied and broadly describedherein, an organic light emitting display (OLED) device may, forexample, include first and second pixels on a substrate, each includinga TFT region and a display region, the display region of each of thefirst and second pixels including a first electrode, an emission layerand a second electrode; a color filter layer in the display region ofthe second pixel; and a reflection preventing layer in the first andsecond pixels, substantially excluding the display region of the secondpixel.

In another aspect of embodiments of the present invention, a method ofmanufacturing an organic light emitting display (OLED) device includingfirst and second pixels on a substrate, each including a TFT region anda display region, the display region of each of the first and secondpixels including a first electrode, an emission layer and a secondelectrode, the method comprising: forming a color filter layer in thedisplay region of the second pixel; and forming a reflection preventinglayer in the first and second pixels, substantially excluding thedisplay region of the second pixel.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of embodiments of the invention and are incorporated inand constitute a part of this application, illustrate embodiment(s) ofthe invention and together with the description serve to explain theprinciple of embodiments of the invention. In the drawings:

FIG. 1 is a cross-sectional view illustrating an organic light emittingdisplay (OLED) device according to the related art;

FIG. 2A and FIG. 2B are plan and cross-sectional views illustrating anOLED device according to an embodiment of the present invention,respectively;

FIG. 3 is a cross-sectional view illustrating a reflection preventinglayer according to an embodiment of the present invention;

FIG. 4 is a concept view illustrating a function of a reflectionpreventing layer according to an embodiment of the present invention;

FIGS. 5A to 5E are views illustrating a manufacturing process forforming a reflection preventing layer according to an embodiment of thepresent invention;

FIGS. 6A to 6D are views illustrating a manufacturing process forforming a reflection preventing layer according to an embodiment of thepresent invention;

FIG. 7 illustrates an OLED device according to an embodiment of thepresent invention;

FIG. 8 is a cross-sectional view illustrating a reflection preventinglayer according to an embodiment of the present invention;

FIG. 9 illustrates an OLED device according to an embodiment of thepresent invention;

FIGS. 10A and 10B are cross-sectional views illustrating an OLED deviceaccording to an embodiment of the present invention; and

FIG. 11 is a cross-sectional view illustrating an OLED device accordingto an embodiment of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Reference will now be made in detail to embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers may be usedthroughout the drawings to refer to the same or like parts.

In the following description, when a first element is positioned “on” or“above” a second structure, the first and second elements may be incontact with each other, or a third element(s) may be interposed betweenthe first and second elements. Also, when terms such as “the first” or“the second” are used to refer to elements, they may be used to separateany one element from other elements, but not necessarily define theorder of corresponding elements.

Hereinafter, an organic light emitting display (OLED) device accordingto embodiments of the present invention and method of manufacturing thesame will be described in detail with reference to the accompanyingdrawings.

FIG. 2A and FIG. 2B are plan and cross-sectional views illustrating anOLED device according to an embodiment of the present invention,respectively.

As illustrated in FIG. 2A, the OLED device may include red (R), green(G), blue (B) and white (W) pixels on a substrate 100. The arrangementof the red (R), green (G), blue (B) and white (W) pixels may vary, andit is not, for example, limited to the above four pixels.

Each of the red (R), green (G), blue (B) and white (W) pixels mayinclude a thin film transistor (TFT) region and a display region. Aplurality of thin film transistors (TFT) and capacitors are formed inthe TFT region, and a light emitting layer is formed in the displayregion. Thus, an image is displayed in the display region.

As illustrated in FIG. 2B, an OLED device may include a substrate 100, athin film transistor 200, a passivation film 300, a color filter layer400, a planarization layer 500, a first electrode 600, a light emittinglayer 700, a second electrode 800, and a reflection preventing layer900.

The thin film transistor 200 is provided on an upper surface of thesubstrate 100. In detail, the thin film transistor 200 is patterned inthe TFT region for each of the red (R), green (G), blue (B) and white(W) pixels.

The passivation film 300 is provided on an entire area of the substrate100 including the thin film transistor 200.

The color filter layer 400 is patterned in the display region for eachof the red (R), green (G), and blue (B) pixels. That is, the red (R)color filter layer 400 is formed in the display region of the red (R)pixel, the green (G) color filter layer 400 is formed in the displayregion of the green (G) pixel, and the blue (B) color filter layer 400is formed in the display region of the blue (B) pixel.

The color filter layer 400 may not be formed in the display region ofthe white (W) pixel. In case of the white (W) pixel, a white-coloredlight, which is emitted from the light emitting layer 700, is emittedintactly through the white (W) pixel. Thus, there may be no need for anadditional color filter layer in the white (W) pixel. Meanwhile, in caseof the red (R), green (G) and blue (B) pixels, when a white-coloredlight, which is emitted from the light emitting layer 700, passesthrough each color filter layer 400, the white-colored light is changedto light with a color of the corresponding pixel.

The planarization layer 500 is provided on an entire area of thesubstrate 100 including the color filter layer 400.

The first electrode 600 is patterned on the planarization layer 500. Thefirst electrode 600 is formed of a transparent conductive material suchas Indium-Tin-Oxide (ITO).

The light emitting layer 700 is patterned on the first electrode 600.The light emitting layer 700 emits a white-colored light. Thus, thelight emitting layer 700 may be formed by a combination of red, greenand blue light emitting layers, or may be formed by a combination oforange and blue light emitting layers. The light emitting layer 700 maybe formed in various types generally known to those skilled in the art.

The second electrode 800 is provided on the light emitting layer 700.

The reflection preventing layer 900 is provided on a lower surface ofthe substrate 100. The reflection preventing layer 900 is provided onthe lower surface of the substrate 100 in a predetermined pattern.

In detail, the reflection preventing layer 900 is formed in the TFTregion for each of the red (R), green (G), blue (B) and white (W)pixels. As the thin film transistor 200 is formed in the TFT region foreach pixel on the upper surface of the substrate 100, an external lightis reflected due to a plurality of signal lines for forming the thinfilm transistor 200. In order to reduce or prevent the external lightfrom being reflected from the TFT region, the reflection preventinglayer 900 is formed in the TFT region for each pixel. The reflectionpreventing layer 900 may be formed to cover an entire TFT region foreach pixel.

Meanwhile, the reflection of an external light also occurs by the firstelectrode 600 in the display region for each of the red (R), green (G),blue (B) and white (W) pixels. In case of the red (R), green (G) andblue (B) pixels, the color filter layer 400 is formed between the firstelectrode 600 and the substrate 100, whereby a considerable amount ofthe external light is absorbed in the color filter layer 400. Thus, aproblem caused by the reflection of external light scarcely occurs inthe display region for each of the red (R), green (G) and blue (B)pixels, whereby the reflection preventing layer 900 may not be needed inthe display region for each of the red (R), green (G) and blue (B)pixels.

However, since the color filter layer 400 is not formed in the white (W)pixel, a problem caused by the reflection of external light may occurtherein. For this reason, the reflection preventing layer 900 isbeneficially formed in the display region of the white (W) pixel.

Thus, the reflection preventing layer 900 is not formed in the displayregion for the pixels that have the color filter layer 400 between thefirst electrode 600 and the substrate 100 (e.g., red (R), green (G) andblue (B) pixels), and the reflection preventing layer 900 is formed inthe display region for the pixel in which the color filter layer 400 isnot formed between the first electrode 600 and the substrate 100 (e.g.,white (W) pixel), whereby luminance is improved by reducing orminimizing the reflection of the external light and decreasing a loss ofemitted light. That is, the reflection preventing layer 900 is notformed in the display region for each of the red (R), green (G) and blue(B) pixels so that it is possible to decrease the loss of light emittedtherein, thereby improving the luminance.

In other words, the reflection preventing layer 900 is formed in the TFTregion for each of the red (R), green (G), blue (B) and white (W)pixels, and the reflection preventing layer 900 is not formed in thedisplay region for each of the red (R), green (G) and blue (B) pixels,whereby it is possible to reduce or prevent the reflection of anexternal light and to reduce or minimize the loss of light, therebyimproving the luminance.

The reflection preventing layer 900 is not formed in an entire area ofthe lower surface of the substrate 100, but is patterned in thepredetermined portion. That is, it is difficult to apply a film-typereflection preventing layer as in the related art. Accordingly, thereflection preventing layer 900 according to an embodiment of thepresent invention is obtained by coating and patterning a coatablematerial layer, which will now be described in detail.

FIG. 3 is a cross-sectional view illustrating a reflection preventinglayer according to one embodiment of the present invention. FIG. 4 is aconcept view illustrating a function of a reflection preventing layeraccording to an embodiment of the present invention.

As illustrated in FIG. 3, the reflection preventing layer 900 accordingto an embodiment of the present invention may include a first alignmentlayer 910, a quarter wave plate (QWP) 920, a second alignment layer 930,and a linear polarization layer (POL) 940.

The first alignment layer 910 is provided on a lower surface of thesubstrate 100, and the quarter wave plate 920 is provided on a lowersurface of the first alignment layer 910.

Since the first alignment layer 910 is aligned in a first direction, thefirst alignment layer 910 aligns a material for the quarter wave plate920, whereby the quarter wave plate 920 has a predetermined polarizingfunction. A manufacturing process thereof will now be described.

The first alignment layer 910 may be formed of a photo-alignmentmaterial such as acrylate-based material or epoxy-based material, butnot limited to these materials.

The quarter wave plate 920 may be formed of reactive mesogen, and thequarter wave plate 920 may have a 45° or −45° transmission axis. Thequarter wave plate 920 may serve to covert a 90° linear polarizationinto a circular polarization and a circular polarization into a 0°linear polarization.

The second alignment layer 930 is provided on a lower surface of thequarter wave plate 920, and the linear polarization layer 940 isprovided on a lower surface of the second alignment layer 930.

Since the second alignment layer 930 is aligned in a second directionwhich is different from the first direction, the second alignment layer930 aligns a material for the linear polarization layer 940, whereby thelinear polarization layer 940 has a predetermined polarizing function. Amanufacturing process thereof will now be described.

The second alignment layer 930 may be formed of a photo-alignmentmaterial such as acrylate-based material or epoxy-based material, butnot limited to these materials.

The linear polarization layer 940 may be formed of a mixture of reactivemesogen and dichromatic dye, or may be formed of a mixture of lyotropicliquid crystal and dichromatic dye. The linear polarization layer 940may have a 90° transmission axis. The linear polarization layer 940linearly polarizes the incident light at about 90° following thetransmission axis.

As described above, the reflection preventing layer 900 according to anembodiment of the present invention may reduce or prevent the externallight from being reflected by the use of quarter wave plate 920 and thelinear polarization layer 940, which will be described in detail withreference to FIG. 4.

As illustrated in FIG. 4, the quarter wave plate 920 is formed under thesubstrate 100, and the linear polarization layer 940 is formed under thequarter wave plate 920. As described above, the linear polarizationlayer 940 linearly polarizes the incident light at about 90°. Also, thequarter wave plate 920 converts a 90° linear polarization into acircular polarization and a circular polarization into a 0° linearpolarization.

Accordingly, the external light is linearly polarized at 90° when theexternal light passes through the linear polarization layer 940, and thelinearly polarized light is then circularly polarized when it passesthrough the quarter wave plate 920. Then, the circularly polarized lightis reflected on the plurality of signal lines of the TFT region and theelectrodes of the display region after it passes through the substrate100, and then the reflected light is linearly polarized at 0° while itpasses through the quarter wave plate 920. As the 0° linear polarizationis substantially orthogonal to the transmission axis of the linearpolarization layer 940, it does not pass through the linear polarizationlayer 940, to thereby reduce or prevent the reflection of the externallight.

FIGS. 5A to 5E are views illustrating a manufacturing process forforming a reflection preventing layer according to an embodiment of thepresent invention, which relates to the manufacturing process of thereflection preventing layer illustrated in FIG. 3.

First, as illustrated in FIG. 5A, the first alignment layer 910 isformed on the lower surface of the substrate 100.

The first alignment layer 910 is obtained by forming a photo-alignmentmaterial layer through a coating process of a photo-alignment materialsuch as acrylate-based material or epoxy-based material, drying asolvent in a drying oven, curing the photo-alignment material layer, andaligning the photo-alignment material layer in the first direction by arubbing or polarized UV irradiation.

Then, as illustrated in FIG. 5B, the quarter wave plate 920 is formed onthe lower surface of the first alignment layer 910.

The quarter wave plate 920 is obtained by coating the lower surface ofthe first alignment layer 910 with reactive mesogen, drying a solvent inthe drying oven, and curing the coated material. This curing process maybe performed by a UV irradiation.

The first alignment layer 910 is aligned in the first direction. Thus,the quarter wave plate 920 is aligned by the first alignment layer 910during the drying process in the drying oven, whereby the quarter waveplate 920 may have a 45° or −45° transmission axis.

After that, as illustrated in FIG. 5C, the second alignment layer 930 isformed on the lower surface of the quarter wave plate 920.

The second alignment layer 930 is obtained by forming a photo-alignmentmaterial layer through a coating process of a photo-alignment materialsuch as acrylate-based material or epoxy-based material, drying asolvent in the drying oven, curing the photo-alignment material layer,and aligning the photo-alignment material layer in the second directionby a rubbing or polarized UV irradiation.

As illustrated in FIG. 5D, the linear polarization layer 940 is formedon the lower surface of the second alignment layer 930.

The linear polarization layer 940 is obtained by coating the mixture ofreactive mesogen and dichromatic dye or the mixture of lyotropic liquidcrystal and dichromatic dye onto the lower surface of the secondalignment layer 930, drying a solvent in the drying oven, and curing thecoated material. This curing process may be performed by a UVirradiation.

The second alignment layer 930 is aligned in the second direction. Thus,the linear polarization layer 940 is aligned by the second alignmentlayer 930 during the drying process in the drying oven, whereby thelinear polarization layer 940 may have a 45° or −45° transmission axis.

As illustrated in FIG. 5E, the reflection preventing layer 900 ispatterned by removing the predetermined portions from the firstalignment layer 910, the quarter wave plate 920, the second alignmentlayer 930 and the linear polarization layer 940.

The process of removing the predetermined portions from the firstalignment layer 910, the quarter wave plate 920, the second alignmentlayer 930 and the linear polarization layer 940 may be performed by aphotolithography process of photo resist coating, exposure, development,etching and stripping.

As described above, the predetermined portions of the first alignmentlayer 910, the quarter wave plate 920, the second alignment layer 930and the linear polarization layer 940, which are to be removed,correspond to the display regions for the red (R), green (G) and blue(B) pixels.

FIGS. 6A to 6D are views illustrating a manufacturing process forforming the reflection preventing layer according to another embodimentof the present invention, which relates to the manufacturing process ofthe reflection preventing layer illustrated in FIG. 3.

First, as illustrated in FIG. 6A, the first alignment layer 910 ispatterned on the lower surface of the substrate 100. The first alignmentlayer 910 is not formed in the display region for each of the red (R),green (G) and blue (B) pixels, but formed in the TFT region for eachpixel and the display region for the white (W) pixel.

The first alignment layer 910 is obtained by forming a photo-alignmentmaterial layer through a coating process of a photo-alignment materialsuch as acrylate-based material or epoxy-based material, drying asolvent in the drying oven, curing the photo-alignment material layer,aligning the photo-alignment material layer for the TFT region for eachpixel and the display region for the white (W) pixel in the firstdirection by irradiating a polarized UV light onto the TFT region foreach pixel and the display region for the white (W) pixel, and removingthe photo-alignment material layer from the display region for each ofthe red (R), green (G) and blue (B) pixels that is not irradiated withthe polarized UV light.

Then, as illustrated in FIG. 6B, the quarter wave plate 920 is formed onthe lower surface of the first alignment layer 910. The quarter waveplate 920 is not formed in the display region for each of the red (R),green (G) and blue (B) pixels, but formed in the TFT region for eachpixel and the display region for the white (W) pixel.

The quarter wave plate 920 is obtained by coating the lower surface ofthe first alignment layer 910 with reactive mesogen, curing the reactivemesogen in the TFT region for each pixel and the display region for thewhite (W) pixel by irradiating a polarized UV light onto the TFT regionfor each pixel and the display region for the white (W) pixel, andremoving the reactive mesogen from the display region for each of thered (R), green (G) and blue (B) pixels that is not irradiated with thepolarized UV.

After that, as illustrated in FIG. 6C, the second alignment layer 930 isformed on the lower surface of the quarter wave plate 920. The secondalignment layer 930 is not formed in the display region for each of thered (R), green (G) and blue (B) pixels, but formed in the TFT region foreach pixel and the display region for the white (W) pixel.

The second alignment layer 930 is obtained by forming a photo-alignmentmaterial layer through a coating process of a photo-alignment materialsuch as acrylate-based material or epoxy-based material, drying asolvent in the drying oven, curing the photo-alignment material layer,aligning the photo-alignment material layer for the TFT region for eachpixel and the display region for the white (W) pixel in the seconddirection by irradiating a polarized UV light onto the TFT region foreach pixel and the display region for the white (W) pixel, and removingthe photo-alignment material layer from the display region for each ofthe red (R), green (G) and blue (B) pixels that is not irradiated withthe polarized UV.

As illustrated in FIG. 6D, the linear polarization layer 940 is formedon the lower surface of the second alignment layer 930, to therebycomplete the pattern for the reflection preventing layer 900. The linearpolarization layer 940 is not formed in the display region for each ofthe red (R), green (G) and blue (B) pixels, but formed in the TFT regionfor each pixel and the display region for the white (W) pixel.

The linear polarization layer 940 is obtained by coating the mixture ofreactive mesogen and dichromatic dye or the mixture of lyotropic liquidcrystal and dichromatic dye onto the lower surface of the secondalignment layer 930, curing the mixture in the TFT region for each pixeland the display region for the white (W) pixel by irradiating apolarized UV light onto the TFT region for each pixel and the displayregion for the white (W) pixel, and removing the mixture from thedisplay region for each of the red (R), green (G) and blue (B) pixelsthat is not irradiated with the polarized UV.

Referring back to FIG. 2B, the OLED device according to one embodimentof the present invention may be manufactured by forming the thin filmtransistor 200 on one surface of the substrate 100, that is, the uppersurface of the substrate 100; forming the passivation film 300 on thethin film transistor 200; forming the color filter layer 400 on thepassivation film 300; forming the planarization layer 500 on the colorfilter layer 400; forming the first electrode 600 on the planarizationlayer 500; forming the light emitting layer 700 on the first electrode600; forming the second electrode 800 on the light emitting layer 700;and forming the reflection preventing layer 900 on the other surface ofthe substrate 100, that is, the lower surface of the substrate 100 inaccordance with the method illustrated in FIGS. 5A to 5E or the methodillustrated in FIGS. 6A to 6D. These elements may be formed by variousmethods generally known to those skilled in the art.

FIG. 7 illustrates an OLED device according to another embodiment of thepresent invention. The OLED device of FIG. 7 is obtained by additionallyforming at least one material layer for the aforementioned reflectionpreventing layer 900 of FIG. 3 in the display region for each of the red(R), green (G) and blue (B) pixels.

In FIG. 3, the material layer for forming the reflection preventinglayer 900 is not formed in the display region for each of the red (R),green (G) and blue (B) pixels. In case of FIG. 7, a first alignmentlayer 910, a quarter wave plate 920 and a second alignment layer 930constituting the reflection preventing layer 900, except a linearpolarization layer 940, are formed in the display region for each of thered (R), green (G) and blue (B) pixels.

The linear polarization layer 940 transmits only a linearly polarizedlight having a specific transmission axis among various transmissionaxes. Thus, if the incident light passes through the linear polarizationlayer 940, it might cause a considerable loss of the light. Meanwhile,the first alignment layer 910, the quarter wave plate 920 and the secondalignment layer 930 correspond to a phase retarder. Thus, even thoughthe light passes through the above first alignment layer 910, thequarter wave plate 920 and the second alignment layer 930, there may beno or small light loss. Accordingly, as illustrated in FIG. 7, eventhough the first alignment layer 910, the quarter wave plate 920 and thesecond alignment layer 930 are formed in the display region for each ofthe red (R), green (G) and blue (B) pixels, there may be no or smalllight loss.

In FIG. 7, all the first alignment layer 910, the quarter wave plate 920and the second alignment layer 930 are formed in the display region foreach of the red (R), green (G) and blue (B) pixels, but not limited tothis structure. That is, at least any one layer of the first alignmentlayer 910, the quarter wave plate 920 and the second alignment layer 930may be formed in the display region for each of the red (R), green (G)and blue (B) pixels. For example, only the first alignment layer 910 maybe formed in the display region for each of the red (R), green (G) andblue (B) pixels, and alternatively, only the first alignment layer 910and quarter wave plate 920 may be formed in the display region for eachof the red (R), green (G) and blue (B) pixels.

FIG. 8 is a cross-sectional view illustrating a reflection preventinglayer according to another embodiment of the present invention.

As illustrated in FIG. 8, the reflection preventing layer 900 accordingto another embodiment of the present invention is obtained byadditionally forming a third alignment layer 950 and a half wave plate(HWP) 960 between a lower surface of a substrate 100 and a firstalignment layer 910.

That is, the reflection preventing layer 900 of FIG. 8 may include thethird alignment layer 950, the half wave plate 960, a first alignmentlayer 910, a quarter wave plate (QWP) 920, a second alignment layer 930and a linear polarization layer (POL) 940, which are sequentiallyprovided on the lower surface of the substrate 100.

In FIG. 3, the reflection preventing layer 900 uses the quarter waveplate 920 as a phase retarder. Meanwhile, the reflection preventinglayer 900 of FIG. 8 uses a combination of the half wave plate 960 andthe quarter wave plate 920 as a phase retarder.

The third alignment layer 950 is provided on the lower surface of thesubstrate 100, and the third alignment layer 950 is aligned in a thirddirection which may be different from the aforementioned first andsecond directions. The third alignment layer 950 aligns a material forthe half wave plate 960, whereby the half wave plate 960 has apredetermined polarizing function.

The third alignment layer 950 may be formed of a photo-alignmentmaterial such as acrylate-based material or epoxy-based material, butnot limited to these materials.

The half wave plate 960 may be formed of reactive mesogen, and the halfwave plate 960 may have a 15° transmission axis. In this case, thequarter wave plate 920 may have a 75° transmission axis.

A manufacturing process for the third alignment layer 950 and the halfwave plate 960 may be similar to the aforementioned manufacturingprocess for the first alignment layer 910 and the quarter wave plate 920illustrated in FIGS. 5A to 5C. That is, the third alignment layer 950may be obtained by forming a photo-alignment material layer through acoating process of a photo-alignment material such as acrylate-basedmaterial or epoxy-based material on the lower surface of the substrate100, drying a solvent in the drying oven, curing the photo-alignmentmaterial layer, and aligning the photo-alignment material layer in thethird direction by a rubbing or polarized UV irradiation. The half waveplate 960 may be obtained by coating the lower surface of the thirdalignment layer 950 with reactive mesogen, drying a solvent in thedrying oven, and curing the coated material. In this case, since thethird alignment layer 950 is aligned in the third direction, the halfwave plate 960 is aligned by the third alignment layer 950 during thedrying process in the drying oven, whereby the half wave plate 960 mayhave a 15° transmission axis.

Although not shown in the drawings, it is possible to additionally format least any one layer of the third alignment layer 950, the half waveplate 960, the first alignment layer 910, the quarter wave plate 920 andthe second alignment layer 930 in the display region for each of the red(R), green (G) and blue (B) pixels.

FIG. 9 illustrates an OLED device according to another embodiment of thepresent invention. In case of FIG. 9, instead of directly forming areflection preventing layer on a lower surface of a substrate 100, thereflection preventing layer 900 is provided on an additional film 901,and then the film 901 is adhered to the lower surface of the substrate100 by the use of an adhesive 902.

In the same manner as in FIG. 3, the reflection preventing layer 900 ofFIG. 9 may include a first alignment layer 910, a quarter wave plate920, a second alignment layer 930 and a linear polarization layer 940.However, it is also possible to apply the structure of FIG. 7 or FIG. 8to the reflection preventing layer 900 of FIG. 9.

The film 901 may be formed of PET-based (polyethylene terephthalate)material, acrylic-based material or TAC-based (Tri-Acetyl Cellulose)material, but not limited to these materials.

The adhesive 902 may be formed of various materials generally known tothose skilled in the art, for example, urethane-based material.

FIGS. 10A and 10B are cross-sectional views illustrating an OLED deviceaccording to another embodiment of the present invention, wherein FIG.10A illustrates red (R), green (G) and blue (B) pixels, and FIG. 10Billustrates a white (W) pixel.

As illustrated in FIG. 10A, the red (R), green (G) or blue (B) pixel isconstructed with a substrate 100, a thin film transistor 200, apassivation film 300, a color filter layer 400, a planarization layer500, a first electrode 600, a bank layer 650, a light emitting layer700, a second electrode 800 and a reflection preventing layer 900.

The substrate 100 is a base substrate, wherein the substrate 100 may beformed of glass or transparent plastic. If needed, the substrate 100 maybe formed of a flexible material.

The thin film transistor 200 is provided on an upper surface of thesubstrate 100, especially, a TFT region. The thin film transistor 200may include a gate electrode 210 patterned on the substrate 100, asemiconductor layer 220 insulated from the gate electrode 210 by a gateinsulating film 150 interposed therebetween, and source and drainelectrodes 230 and 240 provided at a fixed interval from each other andprovided on the semiconductor layer 220. As illustrated in the drawings,the thin film transistor 200 is formed in a bottom gate structure inwhich the gate electrode 210 is positioned below the semiconductor layer220. The thin film transistor 200 may be formed in a top gate structurein which the gate electrode 210 is positioned above the semiconductorlayer 220. The thin film transistor 220 may be formed in various typesgenerally known to those skilled in the art.

The passivation film 300 is provided on the thin film transistor 200,wherein the passivation film 300 is formed in both the TFT region andthe display region. The passivation film 300 may be formed of asingle-layered insulating film, or may be formed of a dual-layeredstructure of inorganic insulating layer and organic insulating layer.

The color filter layer 400 is patterned on the passivation film 300,especially, in the display region. The color filter layer 400 mayinclude red (R), green (G) and blue (B) color filters respectivelyformed for the red (R), green (G) and blue (B) pixels.

The planarization layer 500 is provided on the color filter layer 400.The planarization layer 400 is formed in both the TFT region and thedisplay region, to thereby planarize the surface of substrate 100. Acontact hole is formed in a predetermined region of the passivation film300 and planarization layer 500, whereby a drain electrode 240 of thethin film transistor 200 is exposed via the contact hole.

The first electrode 600 is provided on the planarization layer 500. Thefirst electrode 600 is connected with the drain electrode 240 via thecontact hole. The first electrode 600 may function as an anode.

The bank layer 650 is provided on the first electrode 600. The banklayer 650 is provided on the TFT region, to thereby define the displayregion.

The light emitting layer 700 is provided on the first electrode 600, andis patterned on the display region defined by the bank layer 650. Thelight emitting layer 700 is formed to emit a white-colored light.

The second electrode 800 is provided on the light emitting layer 700.The second electrode 800 may be formed to serve as a common electrode.Thus, the second electrode 800 may be provided on an entire area of thesubstrate 100 including the bank layer 650. The second electrode 800 mayfunction as a cathode.

Although not shown in the drawings, an encapsulation layer forpreventing a moisture permeation from the external may be provided onthe second electrode 800, a sealing layer may be provided on theencapsulation layer, and a protection substrate may be provided on thesealing layer.

The reflection preventing layer 900 is provided on a lower surface ofthe substrate 100. The reflection preventing layer 900 is not formed inthe display region, but formed in the TFT region. A detailed structureof the reflection preventing layer 900 is the same as that of thereflection preventing layer described above, whereby a detaileddescription for the structure of the reflection preventing layer 900will be omitted.

As illustrated in FIG. 10B, the white (W) pixel is constructed with thesubstrate 100, the thin film transistor 200, the passivation film 300,the planarization layer 500, the first electrode 600, the bank layer650, the light emitting layer 700, the second electrode 800 and thereflection preventing layer 900.

Unlike the aforementioned red (R), green (G) and blue (B) pixels, thewhite (W) pixel is not provided with the color filter layer 400. Also,since the color filter layer 400 is not formed in the white (W) pixel,the reflection preventing layer 900 is formed not only in the TFT regionfor the white (W) pixel but also in the display region for the white (W)pixel to reduce or prevent the reflection of an external light in thedisplay region for the white (W) pixel.

FIG. 11 is a cross-sectional view illustrating an OLED device accordingto another embodiment of the present invention. As illustrated in FIG.11, a reflection preventing layer 900 is not provided on a lower surfaceof a substrate 100, but provided on an upper surface of the substrate100.

As illustrated in FIG. 11, the OLED may include the substrate 100, thereflection preventing layer 900, a thin film transistor 200, apassivation film 300, a color filter layer 400, a planarization layer500, a first electrode 600, a light emitting layer 700, a secondelectrode 800 and a sealing layer 850.

The reflection preventing layer 900 is provided on the upper surface ofthe substrate 100. In the same manner as those described above, thereflection preventing layer 900 is not formed in the display region foreach of the red (R), green (G) and blue (B) pixels, but formed in theTFT region for each pixel and the display region for the white (W)pixel.

The thin film transistor 200 is provided on the reflection preventinglayer 900. The passivation film 300, the color filter layer 400, theplanarization layer 500, the first electrode 600, the light emittinglayer 700 and the second electrode 800 may have a similar or identicalstructure to those described above, whereby a detailed description willbe omitted.

The sealing layer 850 is provided on the second electrode 800, tothereby seal the OLED device. In this case, the sealing layer 850 isprovided to seal an entire lateral surface of the reflection preventinglayer 900 so as to reduce or prevent the reflection preventing layer 900from being exposed to the external. If the lateral surface of thereflection preventing layer 900 is exposed to the external, an externalmoisture might permeate through the exposed lateral surface of thereflection preventing layer 900. For this reason, the entire lateralsurface of the reflection preventing layer 900 is sealed by the sealinglayer 850, to thereby reduce or prevent permeation of an externalmoisture. To this end, the reflection preventing layer 900 is notprovided on an entire upper surface of the substrate 100. That is, thereflection preventing layer 900 is not formed in an edge of thesubstrate 100. Accordingly, the sealing layer 850 is formed in the edgeof the substrate 100 without the reflection preventing layer 900.

The above description of the OLED device relates to a bottom emissiontype device in which an image is displayed by the light emitted toward alower direction of the substrate 100, but not limited to this method. AnOLED device according to the present invention may be applied to a topemission type device in which an image is displayed by the light emittedtoward an upper direction of the substrate 100.

According to an embodiment of the present invention, the reflectionpreventing layer 900 is not formed in the display region of the pixelsthat have the color filter layer, but formed in the display region ofthe pixel that does not have the color filter layer, whereby it ispossible to improve the luminance by reducing or minimizing reflectionof an external light and decreasing loss of light.

It will be apparent to those skilled in the art that variousmodifications and variation can be made in the present invention withoutdeparting from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1-20. (canceled)
 21. An organic light emitting display (OLED) devicecomprising: first, second, third and fourth pixels on a first surface ofa substrate, each of the first, second, third and fourth pixelsincluding a display region and a non-display region; a color filterlayer in the first, second and third pixels, a first reflectionpreventing layer in the non-display region of each of the first, secondand third pixels; and a second reflection preventing layer in thenon-display region of the fourth pixel and the display region of thefourth pixel, wherein the first and second reflection preventing layersare on a second surface facing the first surface of the substrate. 22.The OLED device according to claim 21, wherein one of the first, secondand third pixels is any one of red, green and blue pixels, and thefourth pixel is a white pixel.
 23. The OLED device according to claim21, wherein the second reflection preventing layer in the non-displayregion of the fourth pixel has the substantially same thickness as thatof the second reflection preventing layer in the display region of thefourth pixel.
 24. The OLED device according to claim 21, wherein thefirst and second reflection preventing layers include a first alignmentlayer on the second surface of the substrate, a quarter wave plate onthe first alignment layer, a second alignment layer on the quarter waveplate, and a linear polarization layer on the second alignment layer.25. The OLED device according to claim 24, wherein the first and secondreflection preventing layers further include a third alignment layer anda half wave plate between the substrate and the first alignment layer.26. The OLED device according to claim 21, wherein the display region ofeach of the first, second and third pixels is provided with at least anyone of an alignment layer, a half wave plate, a quarter wave plate. 27.The OLED device according to claim 21, further comprising a film on thesubstrate with an adhesive therebetween, and wherein the first andsecond reflection preventing layers is provided on the film.
 28. TheOLED device according to claim 21, wherein a lateral surface of thereflection preventing layer is sealed by a sealing layer.
 29. The OLEDdevice according to claim 21, wherein the display region of each of thefirst, second, third and fourth pixels includes a first electrode, anemission layer and a second electrode, and the emission layer emits awhite light.
 30. The OLED device according to claim 21, wherein thefirst and second reflection preventing layers include a phase retarder.31. An organic light emitting display (OLED) device comprising: first,second, third and fourth pixels on a substrate, each of the first,second, third and fourth pixels including a display region and anon-display region; a color filter layer in the first, second and thirdpixels, a first reflection preventing layer in the non-display region ofeach of the first, second and third pixels; and a second reflectionpreventing layer in the non-display region of the fourth pixel and thedisplay region of the fourth pixel, wherein the second reflectionpreventing layer in the non-display region of the fourth pixel has thesubstantially same thickness as that of the second reflection preventinglayer in the display region of the fourth pixel.
 32. The OLED deviceaccording to claim 31, wherein the first and second reflectionpreventing layers include a first alignment layer on a first surface ofthe substrate, a quarter wave plate on the first alignment layer, asecond alignment layer on the quarter wave plate, and a linearpolarization layer on the second alignment layer.
 33. The OLED deviceaccording to claim 32, wherein the first and second reflectionpreventing layers further include a third alignment layer and a halfwave plate between the substrate and the first alignment layer.
 34. TheOLED device according to claim 31, wherein the display region of each ofthe first, second and third pixels is provided with at least any one ofan alignment layer, a half wave plate, a quarter wave plate.
 35. TheOLED device according to claim 31, further comprising a film on thesubstrate with an adhesive therebetween, and wherein the first andsecond reflection preventing layers is provided on the film.
 36. TheOLED device according to claim 31, wherein a lateral surface of thereflection preventing layer is sealed by a sealing layer.
 37. The OLEDdevice according to claim 31, wherein the first and second reflectionpreventing layers include a phase retarder.
 38. An organic lightemitting display (OLED) device comprising: first, second, third andfourth pixels on a substrate, each of the first, second, third andfourth pixels including a display region and a non-display region; acolor filter layer in the first, second and third pixels, a firstreflection preventing layer in the non-display region of each of thefirst, second and third pixels; and a second reflection preventing layerin the non-display region of the fourth pixel and the display region ofthe fourth pixel, wherein the first and the second reflection preventinglayers include at least one layer that changes a polarization directionof an incident light.
 39. The OLED device according to claim 38, whereinthe at least one layer includes a first layer and a second layer, andwherein the first layer is configured to linearly polarize the light,and the second layer is configured to circularly polarize the linearlypolarized light and linearly polarizes the circularly polarized light.40. The OLED device according to claim 39, wherein a linear polarizationof the linearly polarized light from the circularly polarized light issubstantially orthogonal to a transmission axis of the first layer.